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0answers
30 views

RF information for ship detection

Previously I have asked Space based active optical sensors for maritime surveillance. As a follow on, No SAR sensor is allowed. The suggestion is to use an RF scanner and verify that against collected ...
2
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1answer
105 views

How can i become an astronaut?

I am a 3rd year electrical and electronics engineerincg under graduate student from India. I want to join space industry furthur. How should i select my majors and projects so that i could achieve ...
1
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2answers
66 views

How to compute footprint(size) of beam of sat.system?

I need to compute the footprint (ground area that its transponders offer coverage) of beam diameter. Given different frequencies, distance between a satellite and ground station. I have found the same ...
3
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0answers
32 views

How to calculate the phase angle between satellite and sun with the use of skyfield

With the discussion that took place on answer(s) to How to calculate cone angle between two satellites given their look angles? I would like to ask if my proposal solving that question works like ...
2
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1answer
65 views

Optic communication: day and night

Will launched time of a laser satellite teminal affect to transmission parameters, as data rate, power …? As I know , the main limitation of lasercom is a direct line-of-sight path exists between a ...
3
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0answers
117 views

Why haven't we seen more origami in spacecraft?

I remember watching a few videos awhile back talking about origami designs in spacecraft: Origami in Space: BYU-designed solar arrays inspired by origami Engineering with Origami I've only done a ...
3
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0answers
41 views

Would GRAIL be possible on more distant airless bodies such as Mercury and Callisto?

I was thinking for quite a while about sending this question to Maria Zuber's e-mail address (she was the principal investigator of the GRAIL mission to map the Moon's gravity field), but then I ...
1
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1answer
46 views

Lift and Drag of a Model Rocket

Talking about aerodynamic forces in a model rocket, I believe that Lift and Drag are the components of a net force which acts on the Center of pressure. Knowing this, could I affirm that the net ...
0
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0answers
40 views

Just how much of a spaceflight first will the fourth 2nd stage burn of the Landsat 9 launch be?

USGS.gov's Landsat 9: Payloads stacked atop Atlas V for launch includes the following: A fourth and final burn by the Centaur's RL10C-1 cryogenic main engine executes a deorbit maneuver nearly three ...
2
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1answer
51 views

Why are my empirical and theoretical value of mass flow rate in solid propellant rockets not similar?

For a rocket of: fuel mass $m_f$ = 6 kg, Thrust = 3.1 KN, (vs 4K using reducing catalyst to delay burn time) total powered burn time, $t_b$ = 3.5 s, (using reducing catalyst vs 1.8 sec) This ...
-1
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0answers
33 views

Mass production rate vs mass consumption rate in solid rockets

Do the two terms mean the same? mass production rate, mass flow rate and mass consumption rate in a solid propellant rockets.
2
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1answer
68 views

Why metal tubes of Mechazilla base is thinner, than tubes of it's claw?

Here is the pic for here and other sources. You see that lines at leff ("claw") are thicker than lines ar right ("base"). Why? Intuitively it seems that is should be opposite!
2
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0answers
33 views

Given 10W and a 100 square meter target to look for, which can search a larger area; SAR or LIDAR? (back of spherical cow-shaped envelope question)

Background For the project discussed in Space based active optical sensors for maritime surveillance the concern seems to be that SAR is off the table because a low inclination orbit is in eclipse ...
10
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3answers
1k views

Is it possible for LEO satellites to detect a usable signal from regular mobile phones on the ground?

Background Recently I came across a company called ASTS that claims they will be able to launch LEO satellites with the capability to talk with regular mobile phones. I initially wrote their claims ...
2
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0answers
83 views

SpaceX estimates for Starship and Super-heavy heat shields maximum heating during their orbital and suborbital reentry

Did SpaceX made public their estimates for Starship orbital vehicle heat shield maximum heating (and overall reentry heating profile) during orbital reentry on Earth and same for Super-heavy booster ...
2
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1answer
97 views

How to obtain salt from exoplanets

Is there any way to artificially make salts for humans colonizing planets on a long term basis? It is given that the exoplanet has a water source. So do we hope for the best that it has salt present ...
3
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0answers
69 views

Space based active optical sensors for maritime surveillance

I am designing a CubeSat. The size is yet to be decided as it is based on the sensor. The mission is maritime surveillance (illegal fishing). The payload should be capable of detecting the vessels. ...
2
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0answers
22 views

What is MAHLI's theoretical or expected best optical resolution? How was it defined? Was it verified on Mars?

The block quote in this answer to Has Curiosity ever taken a good hard look at the dirt covering its top surface? Can it? Have individual particles been sized? says that at a focus distance of 2.5 ...
5
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1answer
102 views

What's the point of characteristic energy?

My understanding of orbital mechanics is that delta-v is the most useful notion of ability to change orbits in space, akin to energy being the most useful notion of the ability to do work. But if ...
18
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2answers
1k views

How Did One Stand in The LEM Before Descent? [duplicate]

This is really simple, but i've never seen it discussed. One piloted the Apollo LEM standing up, without many restraints. But before the LEM ignited the descent engine, it was practically in free fall....
4
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0answers
59 views

A question about Nozzle/Extension/Skirt Size

In many rocket engines i see that the thrust chamber and a small part of the nozzle are one piece. Does anyone knows if there's a formula which determines what portion of the nozzle is A ? and how ...
23
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2answers
3k views

When burns are made during inefficient parts of the orbit, where does the lost energy go?

Any Kerbal Space Program player will know that burns prograde and retrograde to the velocity vector are most efficient closest to the body being orbited, while burns normal and anti-normal are most ...
3
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1answer
97 views

Can the cryogenic expansion of liquid oxygen and liquid hydrogen be used to pump a rocket engine?

A common fuel amongst rockets is that of the combination of cryogenic liquid hydrogen and liquid oxygen. I looked at the design of a simple rocket using this cocktail that is the propellant and found ...
4
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0answers
124 views

Exterior "running lights" on ISS?

In Scott Kelley's memoir "Endurance," he describes how challenging it is to navigate the exterior of ISS when in Earth's shadow, and he mentions that his Russian colleagues would just stay ...
1
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0answers
58 views

Right Ascension of the Ascending Node (RAAN) Drift and Correction

This one can be a very short and easy question, but I wanna know the proper answer of them.. Few days ago I got a questions like: "What kind of perturbation(s) can cause drift on RAAN value of a ...
1
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0answers
37 views

Frequency/Spectrum regulation document for laser communication

For RF we have the frequency allocation table, where the RF spectrum is regulated. Optical has big bandwidth, there is a lot of frequency space. How do we regulate optical spectrum? I didnt find any ...
1
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1answer
58 views

Receiver and transmitter in RF/optic satelite communciation: distance vs datarate.v 2

The first version of this question is here. I have read the article "Optical communications work best over relatively short distances in space." by Toyoshima, M., Leeb, W., Kunimori, H. and ...
2
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0answers
54 views

Modifying Starlink / Dragon for orbital communication

In this answer @uhoh notes: The Starlinks currently have three types of internet-related communication: downwards with customers fixed on the Earth's surface below the satellites (except an ...
3
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0answers
59 views

The diagonal braces on the Apollo-era Launch Umbilical Tower (LUT) - oh and the vertical and horizontals too

Can anyone give me a lead on where to find the exact dimensions of the diagonal braces used on the original (Apollo-Era) Saturn V Launch Umbilical Tower (LUT)? In fact, while we are at it, I am ...
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0answers
38 views

Recommended oxidiser for a paraffin wax [closed]

Is it better to use N2O or Oxygen and where could I buy it in Sweden?
10
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1answer
2k views

What keeps the pressure stable inside the ISS?

I'm doing research on life support systems for the design of a Martian scientific base, and I'm having trouble finding information about the specifics racks that keep pressure stable inside the ISS. I ...
2
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0answers
13 views

Does Perseverance have a SAM-like instrument? [duplicate]

Curiosity had an instrument called SAM onboard that did gas chromatography and mass spectrometry. Do any of the instruments on Perseverance include these capabilities? If not, why were they deemed ...
4
votes
1answer
86 views

How does the Falcon 9 upper stage settle its propellants?

I understand the upper stage separates with the use of pneumatic pushers, but what settles the propellants in the upper stage tanks so that the propellant is pushed back to the intake? The pushers ...
1
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2answers
96 views

Is Perseverance really nicknamed Perky?

A MSN article states : Perseverance, nicknamed Perky Is this nickname actually used for Perseverance? By whom? Do the people at NASA colloquially call the rover Perky?
2
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1answer
182 views

What is the max height I can achieve with my solid prop rocket?

For a rocket of: mass, $m$ = 25kg, dry mass $m_f$ = 19 kg, Thrust = 2.1 KN, total powered burn time, $t_b$ = 3.5 s, $I_{sp}$ = 129 I get powered burn height = 549 m and total time to max ht of 5506 ...
-1
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0answers
51 views

Growing plants in space [closed]

What all are the factors that should be taken in consideration while growing plants in an alien planet?(The planet is deficient of nutrients and receives infra red radiations)
10
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3answers
1k views

Agriculture on an exoplanet

If we find a hypothetical Earth-like planet A with a rocky terrain that we could colonize, how would we go about planting the first plants, knowing that there is a deficient of nutrients and the ...
4
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2answers
223 views

How are upper stage engines chilled down?

To chill down an engine, cryogenic propellant is pushed through the engine. This is fine for the first stage because the chill down propellant can just flow out the nozzle and on to the ground/the ...
1
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1answer
98 views

Tilt of Strongback

Roughly by how many degrees does the strongback tilt back during liftoff? does the angle have any significance other than avoiding collision?
1
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0answers
47 views

Which space stations used Torque Equilibrium Attitude? [closed]

My recent question and the related ones made me wonder which space stations in history used Torque Equilibrium Attitude so that one side always faced the Earth and the other faced zenith, and which ...
0
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0answers
101 views

How is it possible that the windows on the ISS mostly face Earth only? [duplicate]

In this article astronaut Clayton C. Anderson states that on the ISS the windows "mosty face Earth, which means that it is only possible to see the stars at the very edges of the windows, and ...
5
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2answers
194 views

Why wasn't the high-speed rotation regime for Ingenuity tested on Earth?

On the NASA website, it says that the propeller on Ingenuity will need to spin faster than what has been done before during all of the previous tests to accommodate for the rarefied atmosphere during ...
7
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1answer
150 views

Is 1/6 G enough for humans to stay healthy?

Micro-G is known to be detrimental to health in the long-term. However, the Moon is at $\frac{1}{6}$ G (while Mars is at ~$\frac{3}{8}$ G). Is $\frac{1}{6}$ G enough for humans to remain healthy in ...
9
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0answers
97 views

Which kinds of survival equipment Crew Dragon has, for a case of emergency landing?

Soyuz spacecraft has various survival equipment for different cases of emergency landing. The cases include water landing, desert landing, snow winter landing (crews have special winter suits). They ...
5
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1answer
71 views

Why does SuperCam need a combination of lasers?

In the video on the NASA website, the speaker says that in SuperCam, we use a combination of lasers Why does the SuperCam need multiple lasers? Did ChemCam also have several lasers?
3
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0answers
24 views

How does SuperCam measure the air?

The NASA website mentions that the SuperCam onboard Perseverance can measure the air. How does it do this? Does it use LIBS? Is the SuperCam more apt at doing these measures than a regular camera?
3
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0answers
73 views

Dragon re-entry flight profile?

I was looking online for a profile depicting the Dragon re-entry similar to those showing the launch and first stage re-entry (e.g. https://www.elonx.net/wp-content/uploads/...
5
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0answers
98 views

Why An-124, not C-5 Galaxy, was used to transport Atlas V?

First stages of Atlas V rocket used to be transported by air on Antonov-124 cargo aircraft. Later Lockheed-Martin switched to transporting by water. Why C-5 Galaxy wasn't used instead of An-124? ...
6
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1answer
428 views

Would the Lunniy Korabl be able to dock with the Oryol spacecraft?

As a successor to the Soyuz program, Russia is currently planning the Oryol/Federatsiya, at first for LEO flights and eventually for lunar ones. Russia wants to build a lunar space station (similar to ...
12
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1answer
3k views

Cost per launch to ISS: Starliner vs Crew Dragon

What is the cost to NASA per launch to ISS of Starliner vs Crew Dragon? The Crew Dragon flights uses the SpaceX Falcon 9-FT with the first stage reusable, along with the partially reusable Crew ...

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